Apparatus for drafting relatively long textile fibers



Oct. 21, 1958 s. P. SPENCER APPARATUS FOR DRAFTING RELATIVELY LONG TEXTILE FIBERS Filed Feb. 10, 1958 INVENTOR. SAMUEL P. SPENCER ATTORN EV United States Patent ce APPARATUS FOR DRAFTING RELATIVELY LONG TEXTILE FIBERS Application February 10, 1958, Serial No. 714,144

3 Claims. (Cl. 19-141) This invention relates to the drafting of relatively long textile fibers of either natural or synthetic material;

It is the general object of the invention to provide improved means for drafting such long fibers uniformly and without breakage.

In a known arrangement, such relatively long fibers are drafted between substantially spaced feed rolls and delivery rolls, and with the latter rolls rotated at substantially greater peripheral speed to produce the desired draft. The feed and delivery rolls are substantially spaced apart to avoid breakage of the long fibers which would be caused by simultaneously gripping both ends of the same fiber.

It is customary to loosely support and guide the fibers from the feed rolls to the delivery rolls between superposed aprons, which are simultaneously advanced at a selected speed which is somewhere between the peripheral speed of the feed rolls and the peripheral speed of the delivery rolls. Drafting of the long fibers by the pull of the more rapidly moving delivery roll is thus permitted, and such drafting is facilitated by the relatively loose disposal of the superposed aprons relative to the fibers.

Apparatus as above described is in common commercial use, and in general is found to be satisfactory. Occasions arise, however, in which certain types of fibers have a tendency to cling to one or the other of the aprons, and to be irregularly released therefrom, thus producing an uneven draft.

It is the general object of this invention to improve the operation of drafting apparatus of the class described by positively driving both the lower and the upper apron and at different relative speeds. The speed ratios may be substantially varied, but in the preferred form the lower apron is advanced more slowly than the periphery of the feed roll, and the upper apron is advanced more rapidly than the periphery of the feed roll.

Such relative and positive movements of the aprons is found to substantially prevent adherence of the fibers to either moving apron, and to avoid irregular or uneven drafting which might be produced by such adherence.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a sectional side elevation of a long draft apparatus embodying this invention; and

Fig. 2 is a front view of the apron rolls, and with the aprons shown in section.

Referring to the drawings, parts of a long draft ap paratus of commercial type are shown, which comprises feed rolls and 11 and delivery rolls 14 and 15. The lower rolls 11 and are continuously rotated and with the peripheral speed of the delivery roll 15 substantially greater than the peripheral speed of the feed roll 11, thereby effecting the desired draft of the fiber strand S.

Intermediate apron rolls 12 and 13 support superposed 2,856,643 Patented Oct. 2 1, 1958 aprons 18 and 19 which are guided around fixed cross bars 20.

The bottom rolls 11, 13 and 15 are mounted in hearing blocks 16 on a stand 17, and the upper rolls 10, 12 and 14 are supported above the lower rolls and are mounted for vertical movement.

The upper feed roll 10 and the upper delivery roll 14 are commonly friction-driven from the lower rolls 11 and 15.

The fiber strand S is delivered to the feed rolls through the usual traversing guide 22, and the reduced or drafted delivery strand is indicated at S.

The construction thus far described is of usual commercial form and operates in the usual manner to draft the relatively long natural or synthetic fibers between the feed rolls 10 and 11 and the delivery rolls 14 and 15.

Reference to Fig. 2 will show that the upper apron roll 12 has raised bands or supporting portions 21 for the edges of the upper aprons 18, but that the roll is recessed between each pair of bands, so that the middle portion of each apron 18 is unsupported and engages the lower apron 19 with loose frictional contact only. The upper apron roll 12 has usually been friction-driven and if positively driven has had equal surface speed.

Long draft apparatus constructed as above described has been found generally satisfactory but, under certain conditions and with certain types of fibers, the fibers have been found to adhere to the apron surfaces and may even be wound around the aprons.

In my improved construction, I provide gears 25 and 26 (Fig. 2) which form a positive drive between the continuously rotated lower apron roll 13 and the upper roll 12 which is supported above the roll 13.

I also form the gears 25 and 26 of different diameters, so that the upper aprons 18 will be driven at a diiferent rate of travel relative to the lower aprons 19. As shown in Fig. 2, the gear 25 is of less diameter than the gear 26, so that the upper aprons 18 travel more rapidly than the corresponding lower aprons 19.

Satisfactory results have resulted from using seventeen teeth in the gear'25 and twenty-one teeth in the gear 26. This gives the upper apron about 24% greater surface speed. It is also found desirable to give the lower aprons a surface speed of 5% to 10% less than the peripheral speed of the feed rolls 10 and 11 but with the surface speed of the upper aprons 18 somewhat greater than the surface speed of the feed roll 11.

While this is found to be a satisfactory ratio, substantial variation may be made in the relative speeds of the two aprons, relative to each other and also relative to the feed roll 11. I

It is found that the differential surface speeds of the upper and lower aprons produce very marked improvements in the operation of the apparatus, and in particular that it prevents adherence of fibers to the aprons and the irregularities in draft which have resulted. from such adherence.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. In a long draft apparatus, a pair of driven feed rolls, means to rotate said rolls, a pair of delivery rolls substantially spaced from said feed rolls, means to rotate said delivery rolls at a substantially greater peripheral speed than the feed rolls, a pair of superposed and loosely contacting aprons mounted between the said pairs of feed and delivery rolls, and means to positively drive said two aprons at relatively different surface speeds.

2. In a long draft apparatus, a pair of driven feed rolls, means to rotate said rolls, a pair of delivery rolls substantially spaced from said feed rolls, means to rotate speed than the feed rolls, a pair of superposed and loosely contacting aprons mounted between the said pairs of feed and delivery rolls, and means to positively drive zsaid two-zaprons. .at arelativelydifferent surface speeds,

and with the lower apron moving more slowly thanthe peripheral. speed of ,the feed rolls.

3. In ;a long vdraft apparatus, -a pair of feed rolls,

.means vtorotatesaid feed rolls, a pair of delivery rolls substantially spaced from saidfeed rolls, means torrotate tsaid delivery rolls at. a substantially greater ,peripl eral speed than the feed rolls, a pair .of :superposed and loosely contacting aprons mounted between the saidgpairs of feed and delivery rolls,, and. means .to positive lydrive saidtjdeliveryrolls at-:asubstantially greater peripheral "said two aprons at relatively"differentsurface speeds-" and with the lower apron rnoving more slowly than the peripheral speed of the feed rolls, and with the upper apron moving more rapidly than the peripheral speed of the feed rolls.

References Cited inithefile of this patent UNITED STATES PATENTS 

